In wet type developing apparatus of this sort, a feed roller in part immersed in a liquid developer is driven to rotate in rotational contact with the developing roller so that the liquid developer is fed onto the developing roller via the feed roller, the developing roller being driven to rotate in rotational contact with the photoconductor drum (see JP 2007-171611 A). And, downstream from an area of rotational contact of the developing roller with the photoconductor drum in a rotation direction of the developing roller, there are disposed a cleaning roller and a cleaning blade for removing a residual liquid toner on the developing roller (see JP 2007-225893 A).
While a residual liquid toner that remains on the surface of the developing roller after the image is developed on the photoconductor drum is recovered into a toner recovery circuit by the cleaning roller and cleaning blade, it has been found that on the developing roller surface after development, such residual liquid toner, by having its carrier liquid component decreased and its density and viscosity raised, tends in nature to accumulate in the form of sludge and to coagulate thereon. As a result, a phenomenon called caking is caused that the coagulated toner adheres and sticks to the cleaning blade, creating streaks on the developing roller surface and thereby exerting an adverse influence on printing quality. Further, a problem also arises that the residual liquid toner made higher in density and viscosity causes piping for toner recovery in the toner recovery circuit to get clogged.
In view of the problems mentioned above, it is an object of the present invention to provide a wet type developing apparatus whereby the residual liquid toner from the developing roller can be well recovered, while avoiding occurrence of a caking phenomenon of residual liquid toner, or preventing the residual liquid toner from caking, at a periphery of a cleaning blade.